A new study from the University of Calgary and other research institutions suggests that taking vitamin D supplements may help reduce the risk of developing dementia.
Dementia refers to a group of conditions that impair at least two major brain functions—most commonly memory and judgment.
Symptoms often include forgetfulness, difficulties with social interactions, and thinking problems severe enough to interfere with everyday life.
Vitamin D is both a nutrient we consume and a hormone produced by our bodies. It is a fat-soluble vitamin best known for helping the body absorb and retain calcium and phosphorus, which are essential for strong bones.
Laboratory research has also shown that vitamin D may help reduce inflammation, control infections, and even slow the growth of cancer cells.
Previous studies have suggested that vitamin D deficiency is linked to a higher risk of dementia. However, the effect of vitamin D supplements on dementia risk has been less clear.
In the new study, researchers analyzed data from 12,388 adults without dementia from the National Alzheimer’s Coordinating Center. They examined whether taking vitamin D supplements was associated with dementia-free survival.
Their findings were striking: participants who took vitamin D supplements had a 40% lower risk of developing dementia compared to those who did not take supplements.
The benefits of vitamin D also differed depending on several factors:
- Sex: Women appeared to benefit more than men.
- Cognitive status: People with normal cognition saw greater protection than those with mild cognitive impairment.
- Genetics: Individuals without the APOE ε4 gene variant—an inherited risk factor for dementia—experienced stronger protective effects than those who carried it.
Based on these results, the researchers suggest that vitamin D supplementation may be a promising strategy for dementia prevention. However, they note that more research, including randomized clinical trials, is needed to confirm these findings.
The study was conducted by Professor Zahinoor Ismail and colleagues and published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.
